The overall aim of the proposed research is to investigate the origins and development of complex categorical representations during the first two years of life. More specifically, we are concerned with the very beginnings of superordinate structures; the acquisition of representations for different individual basic level categories from the same superordinate categories and their "coming together" to form the rudiments of superordinate categories. The proposed research derives significance from the fact that conceptual development -- the acquisition of categorical representations -- underlies mature cognitive functioning from problem solving to the abstraction of meaning from words, sentences and connected discourse. To know the developmental course of this most basic process cannot but help provide insights into understanding deviations from the normal course of cognitive development. Specific experiments are planned to determine the age at which individuated representations can be formed for basic level categories from the same superordinate structure, when these representations begin to cohere to form more global representations, whether individual representations precede more global, undifferentiated categorical representations, and whether methodological factors such as the response measure (preferential looking times following familiarization versus sequential touching) underlie apparent differences to date on the time course for the development of separate representations for basic level categories from the same superordinate category. Studies are also planned to inform us of characteristics that may enhance the formation of these basic level categories, for example, the presentation of exemplars from two as opposed to one basic level category during familiarization and the amount and nature of the familiarization experience. Finally, investigations of various familiarizing experiences on the formation of global categories are planned.